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From: gcarter@globey.cs.wisc.edu (Gregory Carter)
Newsgroups: comp.dcom.modems
Subject: Re: modem frequencies
Keywords: FSK Tone asigments, BELL 103 110-300 baud
Message-ID: <1990Nov2.184823.7202@daffy.cs.wisc.edu>
Date: 2 Nov 90 18:48:23 GMT
References: <1990Oct22.183418.11965@isis.cs.du.edu>
Sender: gcarter@globey.cs.wisc.edu
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Organization: U of Wisconsin CS Dept
Lines: 24

Mmm, its been a little whlie since I was on this topic, but I do believe
for 300 baud the tone asignments are:

The seperation freq's are 100Hz apart with a line of symetry of 1170.
A SPACE is 1070 and a MARK is 1270. This is originate of course.

For autoanswer it is also 100hz with a symetry line of 2125Hz, here a 
SPACE is 2025 and a MARK is 2225.

Well, thats all I know without getting into specifics...which would be
for 1200,2400, Two level Phase Shift Keying, Quadrature four Phase PSK,
Differential Phase Shift Keying, Quadrature Amplitude Modulation QAM.

Look under those topics for a good explanation, Otherwise check out
C Programmers Guide to Serial Communications, by Joe Campbell
Published by Howard Sams Co.

This book has more than anybody wants to know about serial communications,
its 650 pages long and I have read it twice and STILL don't understand
everything in the book.

--Gregory 

**No fancy footers, just an undergrad, no degree.  But I BROWN NOSE VERY WELL.